392,037 papers found

Meta-analysis, a tool for contrasting and combining results from different research studies, has been around now for over 40 years. Journal editors are eager to publish the results from meta-analyses, as they propose to represent the integration of best research evidence with clinical expertise and patient values. Ther…

A focus on novel, confirmatory, and statistically significant results leads to substantial bias in the scientific literature. One type of bias, known as "p-hacking," occurs when researchers collect or select data or statistical analyses until nonsignificant results become significant. Here, we use text-mining to demons…

Widespread use of microarray technology that led to highly complex datasets often is addressing similar or related biological questions. In translational medicine research is often based on measurements that have been obtained at different points in time. However, the researcher looks at them as a progression over time…

A systematic review aims to synthesize all available individual studies on a certain topic and uses explicit and reproducible methods for searching the literature, while a meta-analysis is a mathematical synthesis of the results of these individual studies. Because of the explosion of information in the scientific lite…

It is well known that when a Bayesian meta-analysis includes a small number of studies, inference can be sensitive to the choice of prior for the between-study variance. Choosing a vague prior does not solve the problem, as inferences can be substantially different depending on the degree of vagueness. Moreover, becaus…

The effects of drugs on new cancer and cancer-related death are a major concern. Recently, a meta-analysis raised the possibility that ARBs might have an adverse impact in this respect. This point of view was highly debated until the publication of two other meta-analyses which did not demonstrate any increased risk of…

Animal-pollinated angiosperms either depend on cross-pollination or may also reproduce after self-pollination - the former are thus obligately, the latter facultatively dependent on the service of animal-pollinators. Analogously, flower visitors either solely feed on floral resources or complement their diet with these…

Review papers commonly summarize the current knowledge on a selected topic. These types of papers are considered narrative reviews. Narrative reviews rarely detail the methods used to select the literature included, nor do the authors typically report the purpose of the review. Narrative reviews may be biased due to in…

We describe a new multivariate gamma distribution and discuss its implication in a Poisson-correlated gamma-frailty model. This model is introduced to account for between-subjects correlation occurring in longitudinal count data. For likelihood-based inference involving distributions in which high-dimensional dependenc…

The quantitative analysis of the various clinical researches is carried out by means of special statistical data manipulation. It allows to receive results which cannot be taken from separate researches. In the article methodological bases of the meta-analysis and an opportunity of its application and interpretation in…

A comment on the conduct of a meta-analysis analyzing the effects of statins on cardiovascular and cerebrovascular outcomes is presented in this editorial. Competing risk and risk-stratified analysis models that may be more appropriate for the analysis of clinical trials in general and statin trials in particular are i…

PURPOSE: This paper describes the hierarchy of analytical studies, from the observational studies to the experimental ones. STATE OF THE ART AND MAIN POINTS: Case-control studies, the most frequently performed among analytical studies, may generate or confirm hypotheses. They are of particular use for rare diseases. C…

Epidemiological studies suggest an inverse relationship between physical activity or fitness and blood pressure. In a meta-analysis of 44 randomized controlled intervention trials, the weighted net change in conventional systolic/diastolic blood pressure in response to dynamic aerobic training averaged -3.4/-2.4 mmHg (…

J. B. Miner and N. S. Raju (2004) contended that there are additional studies that compare the risk propensity of entrepreneurs and managers, which, when added to the data from W. H. Stewart and P. L. Roth (2001) and meta-analyzed, produce relationships between risk propensity and entrepreneurial status that are substa…

The authors respond to 2 victimological critiques of their 1998 meta-analysis on child sexual abuse (CSA). S. J. Dallam et al. (2001) claimed that B. Rind, P. Tromovitch, and R. Bauserman (1998) committed numerous methodological and statistical errors, and often miscoded and misinterpreted data. The authors show all th…

A meta-analysis of one approach to measuring expectancy and self-efficacy was conducted. Although used for over 25 years, this measure has yet to be named or integrated across the two theoretical domains. We proposed to label this measure a Multilevel Performance Probability and conducted a meta-analysis. The search fo…

This article demonstrates that the weighting-according-to-the-variance method may introduce biases in meta-analyses of binary outcomes. The weighting favors studies that have certain frequencies of outcome events and weights given to studies of the same size may differ tens to thousands of times merely because of varia…

Preventing cancer depends on the ability to recognize and remove causal factors. In current practice, the methods used to judge cause from epidemiologic, clinical trials and biologic evidence include systematic narrative reviews, criteria-based inference methods, and meta-analysis. Subjectivity and values play a key ro…

1. To state the expected rates of spontaneous improvement for untreated acute otitis media (AOM), recurrent AOM, and otitis media with effusion (OME). 2. To state the expected impact of antibiotic therapy on AOM, recurrent AOM, and OME in terms of the number of children needed to be treated to cure or prevent a single…

Meta-analyses of diagnostic test accuracy are uncommon and often based on separate pooling of sensitivity and specificity, which can lead to biased estimates. Recently, several appropriate methods have been developed for meta-analysing diagnostic test data from primary studies. Primary studies usually only provide bina…